Despite a sea of also-rans in the media-player field and little market share gain by just about anybody against Apple, Samsung keeps plugging away. Its latest effort, the YP-K5, takes a different and interesting direction: It's a compact MP3 player, FM radio and JPEG image viewer designed with a slide-out, pop-up stereo speaker panel to serve up tunes sans headphones.
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Furthering the elements of style, the device features a 1.7-inch, 128 x160-pixel LED color display with a touch-sensitive screen. The 4-Gbyte version, analyzed here, provides storage for up to 25,000 JPEG photos or 1,000 songs and up to 30 hours of claimed playback time.
Samsung was challenged in getting decent audio quality from a pocket-friendly portable, where small size normally means anemic sound. It won't take the place of a nice set of Klipsch speakers, but the sleek, glossy-black K5 does pretty well.
Key to decent audio is a decent amplifier. Samsung chose Wolfson's WM8956 stereo DAC (click here) with an integrated Class-D amp, whose final-stage drive circuits are visible in the lower-left portion of the inset die photo. It produces up to 1 watt/channel with up to 87 percent efficiency, a critical figure of merit in the battery-powered, handheld world. The K5's 830-milliamp-hour lithium polymer battery provides about three watt-hours of total capacity, so acceptable run-times require careful use of the available energy.
All voltage conversion in the K5 comes through switching regulators to maximize conversion efficiency. The boost regulator used to generate the unique voltages for the OLED display is from Maxim (MAX1605, click here). Conversely, key ICs want voltages below the battery's 3.7 V, so a dual-buck converter from Advanced Analogic (AAT2512, click here) is used to regulate down with minimum energy loss.
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No matter what you do on the analog side, however, final results depend on speakers and their associated enclosure. On the transducer front, a pair of 20-mm-diameter speakers are mounted into the cast magnesium rear enclosure. The speakers have unusually long diaphragm travel, suggesting the desire to extract significant bass response. Such a design likely compromises treble response, however, so a small but somewhat intricate speaker-chamber design is used to compensate.
The magnesium casting has internal walls to form a sealed box around each speaker, but a tuned port, exiting to the front-facing side, allows what may be a boost to the upper range of audio frequencies. And the use of a miniature baffle and attention to the speaker enclosure design are clear. If you want a reasonable-sounding speaker-based audio player, give the K5 a listen.
About the author
David Carey is president of Portelligent (www.teardown.com). The Austin, TX, company produces teardown reports and related industry research on wireless, mobile and personal electronics.
